Buffering hotspot on iPhone

OK I have an iPhone 6 I know it is old but oh well some of us can’t afford new ones the problem is I have personal hotspot on my phone but I cannot set it up because it will not stop buffering we have reset the phone took the Sim card out put it back in Soft reset it we’ve done everything imaginable turn off the data turn data back on turn on airplane mode turn off airplane mode etc. etc. and every time it still starts buffering or it will say contact server to set up personal hotspot. The server has even reset the network on the phone reset everything on the phone and nothing is helping why does it still keep buffering